ANDROGEN RECEPTOR GENE (CAG)N REPEAT ANALYSIS IN THE DIFFERENTIAL-DIAGNOSIS BETWEEN KENNEDY DISEASE AND OTHER MOTONEURON DISORDERS

An increase in the number of (CAG)n repeats in the first coding exon o f the androgen receptor (AR) gene has been strongly associated with Ke nnedy disease (KD) (spinal and bulbar muscular atrophy), This is an X- linked hereditary disorder characterized by motoneuron degeneration oc curring in adults together with gynecomastia and hyperestrogenemia, We have performed AR gene molecular analysis in several members of a lar ge family with KD as well as in 25 sporadic patients suffering from he terogeneous motoneuron disease (MND), An increase in the length of the (CAG)n repeats was detected, as expected, in all the affected males a nd in obligatory carrier females, some of which had minor signs of low er motoneuron involvement. There was only one possible exception, one young male with initial signs of the disease, who had an apparent norm al length allele. An increased pathological allele was also found in 3 patients with MND, This indicates that the analysis of (CAG)n repeats of the AR gene plays a role in the differential diagnosis of this het erogeneous group of neurological diseases. (C) 1995 Wiley-Liss, Inc.